In the food canning industry empty cans are loaded onto a conveyor which transports them to a filling system.
If a can is deformed, it may jam the filling system and/or cause damage to the latter. Thus, in the case of nominally round cans, it is desirable to check that cans with an ovality deformation do not pass to the filling system.
Another common fault present in cans is dinting, i.e. a deformation of the can lip. Excessive dinting can also create problems if the can passes to the filling system, in particular because the can may then not seal correctly.
While the present invention is especially suited to the pre-examination of cans, especially round cans used in food canning, it is not limited thereto, and may find application in the final testing of filled and sealed cans, e.g. for dents, and in testing other objects altogether such as bottled and shaped packages.